1. Field of the Invention
The present invention relates a dry etcher including an etching device and a cleaning device, and more particularly, to a dry etcher including an etching device and a cleaning device to which a cleaning process is added so as to be used in a metal layer etching process.
2. Description of the Related Art
In general, an etching process is a process for removing a layer formed below a photoresist so as to correspond to the photoresist formed on a wafer. A method of etching a wafer includes two methods, that is, wet etching and dry etching.
In wet etching, a wafer is immersed in an etching solution and then etched using a chemical reaction. There is an advantage in that wet etching has excellent selectivity and productivity. However, since wet etching is a chemical etching, undercut may occur on the wafer due to isotropic etching. For this reason, it is difficult to form fine patterns by using the wet etching.
In contrast, in dry etching, gas is perpendicularly collided against the wafer and anisotropic etching is performed due to the perpendicular injection of the gas. As a result, it is possible to form fine patterns by using the dry etching. In addition, since chemical solutions are not used in the dry etching, it is possible to perform etching in a clean and safe manner. For this reason, the dry etching has been widely used in recent years. However, because gas physically collides against the wafer, it is not possible to selectively etch specific materials. That is, there is a disadvantage in that the dry etching has poor selectivity.
Further, when etching gas containing chlorine gas or fluorine gas is used as dry etching gas, a chlorine gas layer or fluorine gas layer is formed on the wafer after the etching process. Each of the gas layers is bonded to steam (H2O), and then generates a hydrochloric acid (HCl) or hydrofluoric acid (HF) which is a strong acid. As a result, metal formed on the wafer is etched.
For this reason, a dry etcher using the etching gas, which contains the chlorine gas or fluorine gas, cannot be used to etch the metal layer in the related art. As a result, the dry etcher in the related art has been commonly used to etch only a nonmetal layer.